U.S. Feared Cyanide Attack on New York Subway

United States authorities in 2003 were concerned that Al Qaeda operatives had made plans to carry out a chemical attack on the New York City subway system, according to two former counterterrorism officials. But American intelligence authorities concluded that the plot ultimately had been abandoned, the officials said.

Plans for the attack, which some officials came to believe was called off by a senior member of Al Qaeda, called for using an improvised device to release cyanide into subway cars or other public spaces, said the officials, who would not be named because of the sensitive nature of the information.

The details of the suspected plot were first reported yesterday on Time magazine's Web site, which said the information was contained in a new book by the author Ron Suskind. The magazine is publishing excerpts of the book, "The One Percent Doctrine," in this week's issue.

"We were aware of the plot and took the appropriate precautions," Paul J. Browne, the New York Police Department's chief spokesman, said yesterday when asked about the report. He declined to comment further.

That the sprawling, underground subway system is a possible target for terrorists has long been a concern for law enforcement. After the Sept. 11, 2001, terrorist attacks, the subways received increased police patrols, particularly at the entrances to each of the 16 underwater tunnels. Moves by the Police Department to secure and monitor a system that carries nearly 5 million people a day along 656 miles of tracks reflected the increased jitters about a possible attack.

In February 2003, the counterterrorism arm of the department issued orders for officers to look out for anyone using improvised weapons, like light bulbs laden with chemicals, that could be released in the subways. Officers were ordered to be vigilant and prepared for the release of such substances in densely populated areas.

That same month, city hospitals were wrestling with the issue of how to treat anyone exposed to cyanide. Hospitals were seeking to increase their stocks of medical antidotes to cyanide and other toxic substances, preparing for any potential mass triage.

It is unclear whether those efforts, in February 2003, were linked to knowledge of the alleged plot by Al Qaeda operatives to attack the city's subways.

The account by Mr. Suskind, according to Time, said that American intelligence agents had developed a relationship with an informant from within Pakistan who was connected to Al Qaeda and that the man had told them in March 2003 of the aborted hydrogen cyanide attack on the subways.

According to Mr. Suskind's account, the informant said that while cell members had arrived in the city in 2002, from North Africa, and had researched the locations they had planned to attack, Ayman al-Zawahiri, the top aide to Osama bin Laden, called it off. But American intelligence officials were confused as to why, the account said.

One official who was briefed at the time that the authorities learned of the threat said some in the intelligence community had been skeptical of the supposed plot, particularly of the idea that the plot had been called off by Mr. al-Zawahiri. The plot was said to involve the use of a relatively crude device for releasing the chemical gases.

"This is a simple cyanide thing, two chemicals mixed together, and it releases cyanide gas," he said. "They'd be lucky if they killed everybody on one car — you can do that with a 9-millimeter pistol." He added, "None of it has been confirmed in three years, who these guys were, whether they in fact had a weapon, or whether they were able to put together a weapon, whether that weapon has been defined and what it would cause or whether they were even in New York."

One former official said he believed the basic information about the scheme had been declassified two years ago for distribution to state and local officials.

There were no formal announcements of increased concerns about the city's subway system in March 2003. Mr. Browne would not offer any specifics about when the New York Police Department was informed of the abandoned plot.

Security measures were increased in the subways as a result of the threat, said one of the former officials.

Police Commissioner Raymond W. Kelly has often ticked off the times that subway systems have become the focus of terrorists, emphasizing that an attack could still happen and that plans are constantly being developed to deal with it or prevent it.

The Japanese cult Aum Shinrikyo, which killed 12 people and injured 5,500 in 1995 with a sarin gas attack on subway trains in Tokyo, also attempted an attack using hydrogen cyanide.

Two plastic bags containing the chemical components were found by a cleaning woman near a ventilation grate in a men's restroom in the subway. No gas was produced, but Japanese experts later said the quantity of chemical in the bags could, in theory, have produced enough gas to kill 10,000 people.